The search for a good interface can be overwhelming. You can spend anywhere from $100 to over $3,000 for an interface. Some are Mac or PC-specific. If you're running Pro Tools, you have to buy an interface that's compatible with that software.
So, who is the Apogee designed for? Basically, if you're a Mac user running any Core Audio application (Garageband, Logic Pro, Soundtrack Pro, Digital Performer, Ableton Live, Cubase), and you like to record on-the-go, you'd benefit from having this little box. It's USB-powered, so there's no need for an external power supply. It has a pretty impressive built-in condenser mic, great for recording acoustic guitar and vocals. It also has a breakout cable with a 1/4 Hi-Z input for electric instruments, and a XLR input with Phantom Power for your favorite microphone. In addition, it's about the size of a rather thick cell phone.
The audio quality on this thing is great. If you're familiar with Apogee, you know they have a great reputation for analog/digital/analog converters. Listening to your iTunes library through the One, you may notice a difference. As mentioned above, I really like the built-in mic, and use it for recording most acoustic instruments. There are some great demos of the mic on Apogee's YouTube account. If you don't feel like watching all of them, this is my favorite.
I do have a few (minor) problems with the One, namely:
1. The breakout cable is flimsy. The instrument input no longer works on mine, and I'll have to order another one.
2. The USB cable is flimsy...after dropping the One (while it was plugged in) a few times, I had a hard time getting a good connection between the device and the cable. The USB cable is a common one, though, so I just used one that came with my phone, and it's worked great ever since.
Now would probably be a good time to admit that I'm really hard on my gear. Let's face it, though, if you have a mobile setup, you're gonna drop stuff every now and again.
In conclusion, I don't think there's much competition for the One. The quality and price are pretty much unbeatable. If you need simple, functional recording, follow the link below and start making music!